1. Field of the Invention
The present invention relates to a container opener for opening/closing a sealable container for containing and transferring a plurality of semiconductor wafers oriented horizontally and vertically arranged at predetermined intervals. More particularly, the invention relates to a front opening unified pod (FOUP) opener having a structure such that a drive section for a port door including a detachment/attachment mechanism for detaching/attaching a FOUP door and a holder mechanism for holding the FOUP door, and a drive section for a sensor mechanism for detecting presence/absence, storage condition, and position of wafers contained in the FOUP are arranged in an improved manner.
2. Description of the Related Art
A FOUP opener is adapted to establish communication between a space (a first control space) within a FOUP and a wafer transfer space (a second control space) and to enable transfer of wafers from the first control space to the second control space without exposure to the ambient atmosphere, by means of, for example, a robot. When the wafers are highly-precise wafers having a diameter of 300 mm or more, since such wafers are very expensive, the FOUP opener must satisfy a strict requirement for protection against wafer contamination with dust, specifically, dust particles generated by the FOUP opener itself must be reduced to one particle/b cft or less (0.1 μm particles), and the mapping report error rate must be decreased to once/0.1–1 million wafers or less. In order to detect presence/absence, storage condition, or position of wafers contained in the FOUP before transfer of the wafers, mapping means is provided on either the FOUP opener or a robot. Generally, provision of the mapping means is optional for the FOUP opener and the robot.
FIG. 5 shows a conventional FOUP opener. As shown in FIG. 5, operation of a FOUP opener 01 for detaching a FOUP door 013 from and attaching the FOUP door 013 to/from an opening of a FOUP 010 and for moving the FOUP door 013 vertically is performed within a second control space 200 that maintains a clean room atmosphere. Accordingly, a drive section of a horizontal-movement mechanism 040 for moving a port door 023 and a sensor 070 horizontally and a drive section of a vertical-movement mechanism 050 for moving the port door 023 and the sensor 070 vertically are disposed within the second control space 200. The port door 023 includes a detachment/attachment mechanism for detaching/attaching the FOUP door 013 and a holder mechanism for holding the FOUP door 013 (see Japanese Patent Application Laid-Open (Kokai) No. 11-145244). Reference numeral 014 denotes a semiconductor wafer, reference numeral 021 denotes a port plate, and reference numeral 300 denotes the ambient atmosphere.
Thus, there has been the problem that the drives, which are dust generators, contaminate the second control space 200, which must maintain a clean atmosphere. For example, when a movable member is actuated by a motor or cylinder of a drive section, friction causes generation of dust, which is scattered within a clean room (the second control space 200). Also, an organic substance generated through vaporization of a lubricant applied to a movable member may be scattered within the clean room 200. As a result, the clean room 200 fails to maintain a high level of cleanliness. Furthermore, when the drive sections are to be serviced for maintenance, inspection, or repairs, within the clean room 200, a worker must move or remove equipment in order to establish work space within the clean room 200, resulting in scattering of dust within the clean room 200. Thus, restoration of cleanliness within the clean room 200 to a regular, high level consumes a considerably great amount of time and cost. In order to enable a worker to work within the clean room 200, equipment for removing dust from the worker must be installed, thus incurring further cost.
In order to cope with the above problem, a FOUP opener as shown in FIG. 6 has been proposed (see Japanese kohyo (PCT) Patent Published (re-published) No. WO99/28965). As shown in FIG. 6, a port door is disposed outside a clean room (a second control space 200) for opening/closing and vertical movement of a FOUP door outside the clean room 200. However, since a port door 023 is located between a FOUP 010 and a port plate 021, a gap g is formed therebetween. The gap g creates the possibility of entry of dust into the FOUP 010 (first control space 100) and into the clean room 200 from outside the clean room 200 (from the ambient atmosphere 300), possible adhesion of the dust to the inside surface of FOUP door 013 and to the outside surface of the port door 023, and possible outflow of a large amount of highly clean air to the exterior of the clean room 200.
In the case of the FOUP opener 01 of the patent publication, as the gap g between the FOUP 010 and the port plate 021 becomes larger, the positioning accuracy of the FOUP 010 is reduced due to machining errors, assembly errors, and wear of dock plate 031 for carrying and positioning the FOUP 010 and components of a dock moving mechanism 030. Thus, the presence/absence, storage condition, and position of wafers 014 contained in the FOUP 010 cannot be detected with high accuracy, thus creating possible problems in transfer of the wafers. 014.